The global trend of an aging populace is well known. This creates a challenge in caring for these older people while still respecting their independence and privacy. “Aging-in-place” attempts to enable older people to live in their own homes as long as practical. It should be no surprise that 89% of elders want to stay in their own homes, and from both a personal and a societal perspective aging-in-place is considerably less expensive. However, aging-in-place can also put elders at risk, especially if they live by themselves; as of 2014 approximately 30% of the 40M community-dwelling elders, or about 12M people, live alone. One of the biggest risks to older people living by themselves is falls.
Falls are a leading cause of injury and death for older people. From an individual perspective, one-in-three people over 65, or 14.7M people, fall each year resulting in 2.4M emergency department visits, 722,000 hospitalizations and 22,900 deaths. Even minor falls can result in significant changes in independence. Up to 75% of patients who fall do not recover their pre-fall level of function. If an elder has fallen once, there is a 60% chance they will fall again within a year. Over one half of elders who fall are unable to get up without assistance and they are more likely to suffer additional complications and poorer prognoses. Patients who had fallen at home but were found in less than one hour had a total mortality of 12% but patients who had been helpless for more than 72 hours had a mortality rate of 67%. From a societal perspective, the cost of care for falls in 2012 was about $30B and, given the growing elder population, is anticipated to reach $67.7 billion by the year 2020. Older people fear moving to a nursing home or losing their independence more than they fear death. Unfortunately, for people living alone, a fall can lead to many hours of pain and helplessness on the floor until someone happens to discover them.
In addition to falls, there are other events that may be of interest to those caring for older people who live by themselves. The elder's general level of activity and social interaction is important, especially for people who have congestive heart failure—less activity means they are getting sicker or a potential increase in cognitive decline (dementia/Alzheimer's). Knowing how much a person sleeps, talks on the phone, receives visitors, uses the computer, uses the bathroom etc. can be a predictor of certain illnesses. Knowing if the elder has left the house, or has unanticipated visitors, is important for people with dementia. Unusual toileting patterns are a leading indicator of certain illnesses, especially urinary tract infections.
One may generalize relevant events into three categories. Emergent events (such as falls) needing immediate attention; safety events (such as when a demented person leaves the house) that also requires immediate attention; habitual events (such as sleep patterns, use of the telephone, computer and bathroom or the sound of a doorbell ringing meaning a visitor is present) don't require immediate intervention but are useful for looking at long-term patterns of disease progression. The system described here attempts to provide caregivers timely data on all three of these event categories.
Ideally, since systems to enable aging-in-place are installed in people's homes, they should be as non-obtrusive as possible. It should not require the older person to wear anything or change their lifestyle in any way.
The aging population along with its accompanying desire and challenge of enabling aging-in-place have been apparent for many years, and hence there have been many prior art attempts to develop system that address this concern.
The simplest and most common prior art solution to the detection of emergencies among the elderly is not a true detection system, but rather simply employs a “panic button”. Systems of this type are often called Personal Emergency Response Systems (PERS), and are provided by companies such as Philips LifeLine, Framingham, Mass. If a person has fallen or otherwise needs help, they push a button on a transmitter that is worn around their neck or on their wrist. This transmitter sends a radio signal to a receiver/speaker-telephone, which is plugged into the telephone line. The reception of the radio signal causes the receiver/speaker-telephone to call a preprogrammed telephone number of a response center, where the phone is answered by an operator. The operator can then use the speaker-telephone to ask the victim if they need help. It should be noted that these systems do not generally provide any event data related to habitual or safety events; they are focused on emergent events. Even then, the obvious and significant limitations of this approach include: (i) the need for the elderly person to push the button, which may be difficult if the person is unconscious or has dementia so forgets the button; (ii) the elderly person must always have the button within reach (even at night); (iii) the button/transmitter must be within radio range of the receiver/speaker-phone; and (iv) many elderly people do not enjoy wearing the button.
Another prior art approach is to have a potential fall victim wear an accelerometer. This accelerometer is tuned such that if the person wearing the device falls down, the accelerometer detects the force of impact and sends a radio signal to a similar receiver/speaker-phone as described above. There are many variations on this theme in the art. An example of this type includes a system which describes a fall-sensor accelerometer that is integrated into a mobile phone. Commercial products based on the accelerometer approach are offered by Philips Lifeline (Framingham, Mass.) and Tunstall (Yorkshire, UK). Systems of this type primarily attempt to overcome historically significant limitations such as false alarms generated when the patient sits or lays down abruptly. However, none of the prior art overcomes the fundamental flaw in the approach that the potential fall victim must wear the device on their person constantly—even at night. Other limitations include (i) the relatively high rate of false alarms generated from normal activities of daily living (ADL) or having the sensing accelerometer accidentally drop to the floor; (ii) the relatively high cost of such a device; (iii) like the PERS above, the sensing device must be within radio range of the receiver/speaker-phone; and, similar to the PERS, (iv) many elderly patients do not enjoy wearing the accelerometer.
Yet another prior art solution is a whole-house monitoring system or “Smart Home.” Prior art systems of this type have the potential to indirectly address the problem of fall detection by determining if the elder's normal ADL habits are compromised. These systems rely on sensors placed throughout the elder's home that communicate to a computer that infers ADL activities. For example, if a motion sensor in the bedroom normally senses movement at approximately 7:00 AM every morning, then one day if there has been no motion sensed by 8:00 AM, the system may infer that something is wrong and call for help. Also known are prior art systems which employ an algorithmic approach to gathering data and inferring ADL levels from the data. These systems are severely limited because (i) they only work with a single person living in the home; (ii) they require complex and expensive computer and sensor infrastructures to be installed throughout the entire home; and (iii) most significantly, they typically take many tens-of-minutes to hours before they determine that a pattern is truly changed and hence an alarm for an emergent event should be generated—these are many hours that a fall victim is potentially lying in pain on the floor.
More direct monitoring approaches have also been tried. Indeed, a video monitoring system has also been suggested to detect falls. While this approach again has the advantage of allowing remote detection of falls, it has a very significant limitation in that it requires video cameras to be constantly monitoring all the rooms of the elder's home. This creates obvious and significant privacy concerns.
Another prior art system describes utilizing ceiling-mounted Doppler radar units which determine a person's distance from the floor; if the distance measurement indicates that the person is closer to the floor, an alarm is generated. While this system is valuable in that it is passive (doesn't require the elder to wear anything), the ceiling-mounted devices are difficult to install and expensive. As described, it also only detects falls and not other activities.
Yet another prior art passive fall detection system illuminates a potential fall victim with infrared light and uses infrared depth sensors to determine a point on the person's body, then calculates if that point gets closer to the ground. Infrared depth sensors are used in the Microsoft (Redmond, Wash.) Kinect game sensor. The challenge with these devices is that their resolution decreases significantly as a function of distance; they are optimized for a range of 8-10 feet; it is desirable to be able to monitor an entire room (which could be 20+ feet long) with a single device. Such prior art devices can typically only detect falls and not other events.
Another prior art device is a combination system that uses an on-body accelerometer similar to those described above, and a camera. If the accelerometer detects a fall, an image from the camera is analyzed to confirm the fall. While this approach must help reduce the false alarms created by having only one sensor, it unfortunately has the disadvantages of both accelerometer- and video-based solutions. Namely, it requires the person to remember to constantly wear the accelerometer and has the privacy concerns of video monitoring.
Still another prior art system is a passive fall detection system that uses two sensors to establish upper and lower zones in a room. The outputs of these sensors are monitored and compared to known “fall signatures”; the system essentially determines if infrared energy moves from the upper into the lower zone of the room and, if so, determines that a fall must have occurred. This “dual zone” approach is subject to a high false alarm rate because the system cannot distinguish a fall from laying down in bed or a fast movement to sit down. Since the system only looks at infrared energy it cannot distinguish pets from humans, which also generates false positive alarms. The system also will not work there is more than one person in the room. Finally, while this system can identify movement as well as falls, it cannot identify events such as visitors, bathroom use, etc.
Some prior art systems use a single sensor installed at a known distance from the floor. Based on this known distance, a reference line is established which essentially divides the room into two zones. Motion information from above and below the reference line is analyzed to determine if the motion moved from above the line to below the line; if this is the case it is determined to indicate a fall. Since some systems describe analyzing an image (as opposed to simply the infrared energy), it is hypothetically less prone to false alarms from pets. However, this approach still suffers from high false positives because the system cannot distinguish a fall from laying down in bed or a fast movement to sit down. It is also subject to the obvious disadvantage of needing to be accurately and precisely placed a known distance from the floor, which complicates installation.
Accordingly, a need exists for a less complex, less intrusive and privacy maintaining system which allows the monitoring of various selected parameters inside an occupied space with a goal toward being able to make a determination as to whether or not the occupant of that space is in need of assistance or is exhibiting signs of a change in pattern that might indicate a medical condition or the beginning of some medical condition.